Hopefully you pack hand sanitizer when you travel because you may need it — especially in your hotel room.

If you flick on the light switch or use the remote control to turn on the TV, you’ve just touched two of the dirtiest spots in your room, according to a new study led by Katie Kirsch, an undergraduate student at the University of Houston. Kirsch expected to find that the hotel room toilet and bathroom sink had high levels of germs — which they do — but she was surprised to learn that the most bacteria-ridden surfaces were nowhere near the bathroom.

Kirsch and her colleagues from Purdue University and the University of South Carolina sampled 19 surfaces in three hotel rooms in three states, Texas, Indiana and South Carolina. They tested for levels of total aerobic bacteria — including the bugs that are known to cause illness like streptococcus and staphylococcus — and fecal bacteria.

The germiest surfaces: bathroom sinks and floors, light switches and TV remote controls. The TV remotes had an average of 67.6 colony-forming units of bacteria, or CFU, per cubic centimeter squared. The main light switches in the rooms had an even higher average of 112.7 CFU; they also had the highest levels of fecal bacteria, with an average of 111.1 CFU. Telephone keypads were cleaner, but still contaminated with 20.2 CFU of aerobic bacteria.

According to MSNBC, one study of hospital cleanliness recommended an upper limit of 5 CFU per cubic centimeter squared.

Kirsch’s team also found high levels of bacteria on items in housekeepers’ carts like sponges and mops. In an interview at the General Meeting of the American Society for Microbiology in San Francisco, where the report was presented on Sunday, Kirsch said these items pose a risk for cross-contamination — not only within the same room, but across many rooms. “If you clean the toilet with the sponge and then go to the counter where you put your toothbrush, that bacteria can be transferred,” said Kirsch.

Hotel room surfaces with the lowest levels of contamination were headboards, curtain rods and, surprisingly, bathroom door handles. The researchers couldn’t say whether contact with the germy surfaces they tested would necessarily make you sick — the scientists weren’t specifically testing for illness-causing bacteria — but their findings can provide insight into overall cleanliness. And that was the point of the study: to create a preliminary dataset that would encourage hotels to adopt cleanliness guidelines like those used by the food-service and health-care industries.

“Currently, housekeepers clean 14 to 16 rooms per eight-hour shift, spending approximately 30 minutes on each room. Identifying high-risk items within a hotel room would allow housekeeping managers to strategically design cleaning practices and allocate time to efficiently reduce the potential health risks posed by microbial contamination in hotel rooms,” said Kirsch in a statement.

Overall, though, Kirsch maintains that the hotel industry appears to be doing pretty well in keeping things clean. And some are really getting on board with the effort. MSNBC reports:

Best Western hotels, for instance, just launched a campaign to equip its housekeepers with black light testers to detect unseen bugs. They’re even offering a sanitary wrap for the remotes.

Hampton Inns have launched a campaign emphasizing cleanliness with commercials featuring a hotel guest dressed in a Hazmat suit.

Travelers shouldn’t worry about getting sick while staying in hotels, but bringing along some extra sanitizer — hand gels or wipes to clean off surfaces — wouldn’t hurt.